Information recording and reproducing apparatus

ABSTRACT

A laser waveform generation function is provided in a laser driving waveform generator  2  near a laser  3.  A recording clock generator  9  is included in the laser driving waveform generator  2  to generate a clock with a frequency higher than that of a synchronizing clock  202.  This allows a recording laser current (waveform) to be generated without transmission of a high frequency signal from the modulator  6.  Further, because the synchronizing clock  202  is stopped upon a reproduction operation including reproduction operation in an ID unit, undesired effects on a reproduction operation such as ID reproduction can be reduced. Because the response speed of the recording clock generator  9  can be changed, a high precision clock can be generated. Thus, a high-precision recording laser current (waveform) can be generated.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to an information recording andreproducing apparatus which records information onto a medium using alaser beam with an emission waveform controlled by the recordinginformation, and reproduces information from the medium by use of alaser beam with a lower intensity than that of the laser beam used forrecording. More particularly, the invention provides an optical diskdrive with a circuit to generate a desired waveform for the laser beam.

SUMMARY OF THE INVENTION

[0002] According to an aspect of the present invention, an informationrecording and reproducing apparatus records information using a preciselaser current waveform, and reduces undesired effects duringreproduction operations, such as ID reproduction.

[0003] More particularly, the invention provides an informationrecording and reproducing apparatus, such as an optical disk drive, forrecording information onto a recording medium while changing the laseremissions. The apparatus includes a movable optical pickup unit whichhas a modulator that incorporates data to be recorded onto the recordingmedium using a synchronizing clock, a recording waveform generatorhaving a recording clock generator that generates a recording clockbased on the synchronizing clock. The waveform generator changes thelaser emissions based on the recording clock and the recording data. Acontroller is provided to control the modulator and the recordingwaveform generator. Preferably, the recording waveform generator isformed on a circuit board of the optical pickup unit, and the modulatorand the controller are formed on a circuit board other than that of theoptical pickup unit. The recording clock generator turns the recordingclock on and off based on control by the recording controller.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004]FIG. 1 is a timing diagram showing a control operation of thepresent invention;

[0005]FIG. 2 is a diagram showing a modulator and a circuit forproviding a laser driver;

[0006]FIG. 3 is a diagram showing the relation among recording data, asynchronizing clock, a recording clock and a recording laser waveform;

[0007]FIG. 4 is a diagram showing a recording clock generator accordingto a first embodiment;

[0008]FIG. 5 is a diagram showing the recording clock generatoraccording to a second embodiment;

[0009]FIG. 6 is a diagram showing a first embodiment of an informationrecording and reproducing apparatus using the modulator and the waveformgenerator in FIG. 2;

[0010]FIG. 7 is a diagram showing an example of a control interfacesignal;

[0011]FIG. 8 is a diagram showing a second embodiment of the informationrecording and reproducing apparatus using the modulator and waveformgenerator in FIG. 2;

[0012]FIG. 9 is a diagram showing an example of an automatic executioncircuit;

[0013]FIG. 10 is a diagram showing an example of an operation sequencein a first embodiment of the information recording and reproducingapparatus;

[0014]FIG. 11 is a diagram showing an example of an operation sequencein a second embodiment of the information recording and reproducingapparatus;

[0015]FIG. 12 is a diagram showing an example of an operation sequencein the information recording and reproducing apparatus of the first andsecond embodiments;

[0016]FIG. 13 is a diagram showing an example of an operation sequencein the information recording and reproducing apparatus of the first andsecond embodiments;

[0017]FIG. 14 is a diagram showing an example of an operation sequencein the information recording and reproducing apparatus of the first andsecond embodiments;

[0018]FIG. 15 is a diagram showing an example of an operation sequencein the information recording and reproducing apparatus of the first andsecond embodiments;

[0019]FIG. 16 is a diagram showing a modulator (laser waveformgenerator) and a laser driver; and

[0020]FIG. 17 is a timing diagram showing timing of a modulator (laserwaveform generator) and a laser driver.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

[0021] One embodiment of an information recording and reproducingapparatus of the present invention includes, a modulator for providingrecording data to be recorded onto a recording medium; a synchronizingclock; a recording waveform generator having a recording clock generatorfor generating a recording clock based on the synchronizing clock forchanging the amount of laser emission based on the recording clock andthe recording data; and a recording controller for controlling themodulator and the recording waveform generator. In this embodiment, therecording clock generator has a clock generation/stop function and aresponse speed changing function, and the recording controller generatesa clock generation/stop control signal and a response speed changingsignal for control of the recording clock generator.

[0022]FIG. 2 shows an embodiment of a modulator and waveform generatorcircuit for controlling a laser. The waveform generator 2 includes an LDdriver 11 comprising, e.g., current switches and an adder as shown inFIG. 16, but is not limited to this arrangement. Further, waveformgenerator 10 and the LD driver 11 are not necessarily integrated, butmay be separately constructed. Recording controller 8 provides start andstop signals to a recording-clock generator and also provides a signalto the recording-clock generator to change its response speed.

[0023] In FIG. 2, signal lines transmit a synchronizing clock 202,recording data 203, a recording gate signal 204, a response speed signal206 and an oscillation start/stop signal 207. These are connectedbetween the modulator 6, the recording controller 8, and the waveformgenerator 2, using a flexible cable (not shown) or the like. Thewaveform generator 2 is preferably provided on an optical pickup unit(not shown), and thus moves with movement of the optical pickup unit.The modulator 6 and the recording controller 8 are provided on asubstrate (not shown) in the information recording and reproducingapparatus, and thus do not move with the optical pickup unit.

[0024] The flow of signals between the modulator 6 and the waveformgenerator 2 is described with reference to FIG. 3 showing the relationamong the recording data 203, the synchronizing clock 202, the recordingclock 201 and the recording laser waveform 209. Recording clockgenerator 9 generates the recording clock signal 201 based on thesynchronizing clock signal 202 from the synchronizing clock generator 7,and sends the recording clock 201 to the waveform generator 10. Thewaveform generator 10 generates the waveform for controlling current tothe recording laser 209, based on the recording data (e.g., NRZ signal)203 sent from the modulator 6 and the recording clock 201 sent from therecording clock generator 9. The emission of laser 3 changes inaccordance with changes of the waveform of the laser current 209. The LDdriver 11 drives the laser 3 based on the recording laser current 209,thus causing the laser to record on an information recording medium.

[0025] In these figures, the synchronizing clock 202 is one-fourth thefrequency of the recording clock 201. The frequency of the synchronizingclock 202 is not limited to this frequency, but may be an arbitrary 1/Nfrequency. Because a Phase Locked Loop circuit (PLL) is often used asthe recording clock generator 9, and to simplify circuit construction,it is preferable that N be set to a power of 2. Further, as N increases,jitter of the synchronizing clock increases, therefore, it is preferablethat N be determined in view of these conditions.

[0026] The signal timing of the modulator 6 and the waveform generator 9are described with reference to FIG. 1. During a reproduction operation,because the recording clock 201 is not necessary, the recordingcontroller 8 issues the oscillation start/stop signal 207 to therecording clock generator 9 to stop oscillation of the recording clock201. Accordingly, interference with other circuits during reproductionoperations is prevented. Further, the recording controller 8 stopssupply of the synchronizing clock 202 from the synchronizing clockgenerator 7 to the recording clock generator 9.

[0027] For a recording operation, it is necessary to start oscillationof the recording clock 201. Generally, during a seek operation formovement of the head to a target position, the oscillation of therecording clock 201 is started. In this case, the synchronizing clock202 is supplied from the synchronizing clock generator 7 in modulator 6.Upon start of the oscillation of the recording clock 201, because therecording clock 201 is not synchronized with the synchronizing clock202, a synchronizing operation is performed. To complete thesynchronizing operation quickly, it is necessary to increase the loopgain of the PLL of the recording clock generator 9. Because therecording clock generator 9 is easily influenced by externaldisturbances when the loop gain is high, it is preferable to reduce theloop gain after the synchronization, i.e., to set the response speed toa lower speed. For this purpose, the response speed of the recordingclock generator 9 is changed by the response speed changing signal 206issued from the recording controller 8. Thus, a high precision recordingclock can be generated by changing the circuit characteristic of therecording clock generator 9. Note that in FIG. 1, the response speed isswitched to a lower speed after the recording operation for one sector,however, it may be arranged such that the response speed is set to ahigh speed only during a seek operation period, then switched to thelower speed upon start of the recording operation.

[0028] Next, an example of the structure of the recording clockgenerator 9 is described with reference to FIG. 4. This structure is aPLL, a well known circuit. In FIG. 4, “fin” corresponds to thesynchronizing clock 202; “Gp”, to the gain of phase comparator 91; “Gf”,to the gain of low-pass filter 92; “Gal” and “Ga2”, to the gains ofamplifiers 93 a and 93 b; “Gv”, to gain of a voltage control oscillator94; “N” to a feedback frequency ratio of a frequency divider 95; and“fout” to an output clock, i.e., recording clock 201. Note that the“fout” 201 is not necessarily the recording clock 202, but a clock 15obtained by dividing the “fout” may be used as the recording clock 202.The loop gain of the PLL is changed by selecting the gain Ga1 of theamplifier 93 a or the gain Ga2 of the amplifier 93 b.

[0029] Returning to the explanation of the control of modulator 6 andthe waveform generator 9, after completion of the recording operation,because the recording clock 201 is not necessary, the recordingcontroller 8 issues the oscillation start/stop signal 207 to therecording clock generator 9 to stop the oscillation of the recordingclock 201. Accordingly, interference with other circuits during thereproduction operation is prevented. Further, the recording controller 8prevents supply of the synchronizing clock 202 from the synchronizingclock generator 7 to the recording clock generator 9.

[0030] Note that as shown in FIG. 1, the synchronizing clock 202 isstopped in a sector ID unit so as to prevent interference by thesynchronizing clock 202 to the reproduction operation. In this case,when the recording clock generator 9 detects a dropout (stoppage) of thesynchronizing clock, it holds the oscillation frequency at the valuebefore the dropout, and the recording clock 201 is continuously suppliedto the waveform generator 10. Accordingly, in a recording operation, itis not necessary to perform a synchronizing operation at each sectorchange, therefore, it is not necessary to change the response speed ofthe recording clock generator 9 using the response speed changing signalat each sector change. Thus, stable and high precision recordingoperations can be performed.

[0031]FIG. 5 is a second example of the recording clock generator 9. Inthis example, the loop gain is changed by changing the feedbackfrequency dividing ratio N of the recording clock generator (PLL) 9. Ifthe ratio N is reduced (the minimum value is 1), the gain increases. Thegain is changed by selection of an N=1 frequency divider 95 a and an N=4frequency divider 95 b. Note that when the feedback frequency dividingratio N is changed, the frequency of the synchronizing clock 202 must bechanged at the same time. Accordingly, the response speed is changed bythe response speed changing signal 206, and at the same time, thefrequency dividing ratio of the synchronizing clock generator 7 in themodulator 6 is changed by selection of frequency dividers 71 and 72.Using this method, the change of response speed is achieved with adigital circuit. Because loss of synchronization might occur, it ispreferable that the change of response speed be performed when the PLLholds the value prior to the change of frequency dividing ratio as aphase comparison error. At the control timing in FIG. 1, it is realizedby changing the frequency dividing ratio during an ID reproductionoperation.

[0032]FIG. 6 illustrates a first embodiment of the information recordingand reproducing apparatus using the above-described modulator and thelaser driving waveform generator. In this embodiment, control by thewaveform generator 2 can be realized, not by providing signal lineshaving independent functions, but by providing a single controlinterface signal 210 to transfer data corresponding to the controlcontent. In FIG. 6, a signal line to transmit the synchronizing clock202, the recording data 203, a recording gate signal 204 and the controlinterface signal 210 is connected as a flexible cable (not shown)between a signal processor 1 and the laser driving waveform generator 2.

[0033] Because the waveform generator 2 is provided in the opticalpickup unit (not shown), the waveform generator 2, including therecording clock generator (PLL) 9, moves with the movement of theoptical pickup unit. On the other hand, the signal processor 1,including the modulator 6, is provided on the substrate (not shown)fixed to the information recording and reproducing apparatus. Thus, thesignal processor 1 does not move with the movement of the optical pickupunit.

[0034]FIG. 7 is an example of the control interface signal 210 in serialform, although no limitation is posed on the format of the controlinterface signal 210. The serial interface signal includes three signallines, one for a transfer enable signal, one for a transfer clock, andone to transfer data. When the level of the transfer enable signal is“H”, the interface is in an operating state, and the transferred data isprovided in synchronization with the transfer clock. In the transferdata the first-half 8 bits represent an address of one of varioussetting registers included in the laser driving waveform generator, andthe last half 8 bits represent data written at the address.

[0035] The waveform generator 2 receiving the data separates thetransfer data into the register address and the register setting datausing an interface circuit 14, and writes the data into a register ofthe designated address. The signal processor 1, including an interfacecircuit 12 between the modulator 6 and the waveform generator 2, isconnected to the higher-level device interface circuit 5, for datatransfer with a higher level external device such as a PC (not shown).

[0036] The higher level device also issues recording and reproductionrequests (commands) and provides data to be recorded to the informationrecording and reproducing apparatus. A microprocessor 4 receives thesecommands from the higher-level device interface circuit 5, and controlsthe respective elements in the information recording and reproducingapparatus. Similarly, the waveform generator 2 of the present inventionis controlled by the microprocessor 4 placing predetermined informationinto the interface circuit 12 to drive the control interface circuit 14.

[0037]FIG. 10 shows the control procedure (operation sequence) fornormal operation according to the present invention. Setting (1) is usedfor a high-speed synchronization mode with oscillation of the recordingclock (ON), while setting (2) is used for a low-speed synchronizationmode with oscillation of the recording clock (ON). Setting (3) is usedfor a recording clock stop (OFF) mode. When a recording command isissued from the higher-level (external) device, the microprocessor 4places the information into the interface circuit 12 to drive thecontrol interface circuit 14, which sets the waveform generator 2 to apredetermined state. At the same time, microprocessor 4 also controlsclock generator 7 in modulator 6, to generate the synchronizing clock202. Microprocessor 4 also sets a recording start sector in the IDdetector 13. When the ID detector 13 detects the recording start sector,it notifies the recording controller 8 of the detection of the recordingstart sector. The recording controller 8 controls the modulator 6, tosend the recording gate 204 (/WR) and the recording data 203 (NRZ) tothe waveforn generator 10. As described above, the waveform generator 10generates the recording laser current waveform 209 based on therecording data (e.g., NRZ signal) 203 from the modulator 6 and therecording clock 201 from the clock generator 9. Then, the LD driver 11drives the laser 3 based on the waveform 209, to perform recording onthe information recording medium.

[0038] When recording for a sector is complete, microprocessor 4 placesthe setting (3) information into the interface circuit 12 to drive thecontrol interface circuit 14, to set the waveform generator 2 to thesetting (2) within an ID reproduction period following the recording.When a readout command (reproduction request) is issued, themicroprocessor 4 places the information of the setting (3) into theinterface circuit 12 to drive the control interface, to set the laserdriving waveform generator to the setting (3).

[0039] In the recording and reproducing apparatus of the firstembodiment described above, the waveform generation function isperformed not by a circuit on the substrate within the apparatus (themodulator 6), but by a circuit on the optical pickup unit near the laser3. Further, the clock generator 9 is included in the circuit on theoptical pickup unit (the waveform generator 2), to generate a clockhaving a frequency higher than that of the synchronizing clock 202. Inthis construction, because a recording laser waveform can be generatedwithout transmission of a high frequency signal from the modulator 6,the waveform generator 2 is not easily influenced by delay among thesignals, and information can be recorded with high precision using theprovided waveform. Further, because the supply of the synchronizingclock 202 is stopped at a reproduction operation, including the sectorID reproduction operation, undesirable effects on the reproductionoperation are reduced. Further, because a high precision clock can begenerated by changing the response speed of the clock generator 9, ahighprecision recording laser current waveform can be generated, andinformation can be recorded with high precision.

[0040]FIG. 8 shows a second embodiment of the information recording andreproducing apparatus to which the above-described modulator and thelaser driving waveform generator are applied. Explanation correspondingto those same aspects of the first embodiment are omitted. The secondembodiment differs from the first embodiment by providing an automaticexecution circuit 15 in the interface circuit 12. The other componentsare same as those in the first embodiment, and therefore, are notdiscussed again.

[0041] In the first embodiment, the microprocessor 4 must always detectthe start and ending timing of a sector to control the waveformgenerator 2. This, however, may cause an overload on the microprocessoroperation. Because the automatic execution circuit 15 is provided, themicroprocessor 4 outputs recording and reproduction requests to therecording controller 8 regardless of sector status. Thus, it is notnecessary for the microprocessor 4 to always exactly detect the startand ending timing of a sector; therefore, the load on the microprocessor4 can be reduced, improving processing speed of the entire apparatus.

[0042]FIG. 9 is an example of the automatic execution circuit 15. Inthis figure, registers 151 to 153 for holding 3 types of settings areprovided. When power to the drive is turned on, for example, when a diskis inserted, or when a disk is exchanged for another disk, settinginformation is written from the microprocessor. The recording controller8 provides 3 types of trigger signals 211 a, 211 b, and 211 e to theautomatic execution circuit 15. The automatic execution circuit 15provides a start signal 212 for the interface circuit 12. At the sametime, the automatic execution circuit 15 supplies corresponding registerdata 213 to the interface circuit 12. When the start signal 212 isreceived, the interface circuit 12 reads the register data 213 from theautomatic execution circuit 15, and supplies the data to the controlinterface 210.

[0043]FIG. 11 is an example of the operation sequence of the secondembodiment. For recording, the microprocessor provides a recordingrequest to the signal processor 1 to set a recording head sector in theID detector 13. If the recording controller 8 does not perform otherrecording reproduction at that time, it supplies a trigger signal 1 (211a) to the automatic execution circuit 15. The automatic executioncircuit 15 operates the interface circuit 12, and outputs the content ofthe setting register 1, set in advance, to the laser driving waveformgenerator 2, so as to set the state of the setting (1). At the sametime, the recording controller 8 provides the synchronizing clock 202.When the ID detector 13 detects the recording head sector, recording isstarted. When the recording for a sector has been completed, therecording controller 8 sends a trigger signal 2 (211 b) to the automaticexecution circuit 15 within the ID reproduction period following therecording for that sector. The automatic execution circuit 15 operatesthe interface circuit 12 to supply the contents in the setting register2 to the waveform generator 2, to set the waveform generator to thestate of the setting (2) . If the response speed is changed by changingthe frequency dividing ratio of a reference clock, the frequencydividing ratio of the synchronizing clock generator is changed at thesame time.

[0044] For reproduction operations, the microprocessor 4 sends areproduction request to the signal processor 1, setting a reproductionhead sector address. The recording controller 8 provides a triggersignal 3 to the automatic execution circuit 15 after the recording endsector. The recording controller performs a recording operation uponreception of the reproduction request, or after the current sector. Theautomatic execution circuit 15 operates the interface circuit 12 totransmit the contents set in the setting register 3 to the waveformgenerator 2, to set the waveform generator to the state of the setting(3), i.e., recording clock stop state.

[0045] According to the information recording and reproducing apparatusof the second embodiment as described above, in addition to theadvantages of the first embodiment, the automatic execution circuit 15reduces the load on the microprocessor 4 and improves the operationprocessing speed of the entire apparatus.

[0046] Next, various operating conditions of the recording andreproducing apparatus in the first and second embodiments are described.The following description is of the first embodiment; however, setting(1) means issuance of the trigger signal 1 (211 a) in the secondembodiment; setting (2) means issuance of the trigger signal 2 (211 b)in the second embodiment; and setting (3) means issuance of the triggersignal 1 (211 c) in the second embodiment are used.

[0047]FIG. 12 is an example where a sector designated by themicroprocessor 4 has a defect and recording is started at the nextsector. In this case, the synchronizing clock 202 is provided in thedeficient sector, and the shift to the setting (2) is performed withinthe ID reproduction period between the end of the deficient sector andthe start of the actual recording sector.

[0048]FIG. 13 is an example where the microprocessor 4 provides arecording request during a reproduction operation and a recordingoperation is started within a short period after the completion of thereproduction. Because the recording controller 8 is performing areproduction operation when the recording request is received, thesetting is not immediately shifted to setting (1), but the recordingcontroller 8 changes the setting (1) after the reproduction sector. Asin the above-described case, the shift to setting (2) is made after therecording head sector.

[0049]FIG. 14 is an example where a second recording command is setduring a recording operation based on a first recording command(recording request), and the recording operation is continued withoutshifting to a reproduction operation. In this case, because areproduction command is not set, the setting is not shifted to thesetting (3), but is shifted to setting (1) after the end recordingsector in the preceding recording operation. Then, after the recordinghead sector in the subsequent recording operation, the setting isshifted to setting (2).

[0050]FIG. 15 shows another control method with a similar situation toFIG. 14. If the recording operation is continued, the setting (2) set inthe preceding recording operation is continued without changing thesetting (without issuance of the trigger signals 1 and 2 in the secondembodiment).

[0051]FIG. 16 shows a laser waveform generating method for aninformation recording and reproducing apparatus. In FIG. 16, a modulator6′ performs encoding on recording information sent from a higher leveldevice (not shown) by a predetermined modulation method. An emissioncurrent for a laser diode 3 is turned on and off based on a controlsignal by current switches 111 to 113 provided in laser driver 11′. Acurrent adder 114 adds the currents supplied from the plural currentswitches. Control signals 1 to 3 (214 to 216) are provided from awaveform generator 10′, and included in the modulator 6′.

[0052]FIG. 17 is a timing diagram of an example of recording data 203after modulation and the control signals 1 to 3. In FIG. 17, “mark” is aportion where high laser power irradiates a medium to cause a largeamount of change, and “space” is a portion where lower laser powerirradiates the medium to cause, or not to cause, a small amount ofchange. In this waveform example, when a mark is being recorded, laseremission is controlled at the same period as that of a recording clock201. At the end of the mark, the laser power is lowered, and after tworecording clock periods, the laser power is reduced to the space level.

[0053] To generate this laser emission waveform, the control signals areas follows. Control signal 1 (214) with the same period as that of therecording clock 201, is provided only in the mark portion. Controlsignal 2 (215) operates between the end of the mark and the front end ofthe space in a direction to cut off the current, while control signal 3(216) operates to pass the current through from the rising edge of thecontrol signal 2 through the space portion to the end of the markportion. These control signals are generated in correspondence withrecording data 203. As the current switches 111 to 113 operate to passpredetermined currents when the levels of the control signals are “H”,as a recording laser current 209, a high current in a pulse emissionregion is the result of addition of the current passed by the currentswitch 1 and the current passed by the current switch 2, while a lowcurrent is only the current passed by the current switch 2. In acool-down region, when all the current switches are turned off, nocurrent flows. In an erase region, as the current switches 2 and 3 passcurrents, the recording laser current is the sum of addition of bothcurrents.

[0054] In the above-described laser waveform generation method, it isnecessary to supply a plurality of control signals synchronized withrecording data to current switches. Further, to control the laser at ahigh frequency, generally, the current switches are provided near thelaser. Thus, they are preferably mounted on an optical pickup unit wherelaser, optical parts, a laser positioning control mechanism and the likeare integrated. The current switches are positioned away from a signalprocessor including the modulator and the waveform generator. In theabove-described example of FIG. 16, the control signals 1 to 3 (214 to216) from the modulator 6′ (the waveform generator 10′) are transmittedvia a signal line, such as a flexible cable, to the laser driver 11′.

[0055] In a DVD (Digital Versatile Disc) or the like, and in informationrecording and reproducing apparatus, the increase in density ofrecording medium and the increase in recording/reproduction processingspeed of the information recording and reproducing apparatus areoccurring. With the development of such increases in recording mediumdensity and processing speed, the precision of signals must be furtherimproved by increasing the signal frequency, reducing the signal delaytime and the like. However, in conventional laser waveform generationmethods, it is difficult to respond to these requirements, and a laserdriving waveform generator with a new construction is needed.

[0056] The preceding has been a description of the preferred embodimentof the invention. It will be appreciated that deviations andmodifications can be made without departing from the scope of theinvention, which is defined by the appended claims.

What is claimed is:
 1. An information recording and reproducingapparatus comprising: a modulator for generating recording data to berecorded onto a recording medium using a synchronizing clock; arecording waveform generator, including a recording clock generatorwhich generates a recording clock based on the synchronizing clock, forchanging a laser emission based on the recording clock and the recordingdata; a recording controller coupled to the modulator and to therecording waveform generator for controlling them; and wherein therecording clock generator has a clock generation/stop function and aresponse speed changing function, and wherein the recording controllerprovides a clock generation/stop control signal and a response speedchanging signal, and controls the recording clock generator with atleast one of the clock generation/stop control signal and the responsespeed changing signal.
 2. The information recording and reproducingapparatus according to claim 1, wherein the recording controllercontrols the modulator and the recording waveform generator, and whereinupon reproduction of data, the recording controller stops generation ofthe recording clock and the synchronizing clock with the clockgeneration/stop control signal, and further wherein upon recording data,the recording controller generates the recording clock and thesynchronizing clock, and upon start of recording, sets the responsespeed to a high speed, and sets the response speed to a low speed afterelapse of a predetermined period.
 3. The information recording andreproducing apparatus according to claim 2, wherein, in the recordingmedium, regions where predetermined information are recorded areprovided as sectors, each sector having a head where an address signalindicative of the position of the sector is recorded in advance, andwherein the response speed is changed within an address signal periodbetween after the end of recording for the sector and the start ofrecording for the next sector.
 4. The information recording andreproducing apparatus according to claim 1, wherein the response speedchanging function is performed by changing the ratio between a frequencyof the recording clock and the synchronizing clock, and wherein aconstant of a circuit of the recording clock generator and a frequencyof the synchronizing clock are changed.
 5. An information recording andreproducing apparatus comprising: a signal processor having a recordingdata generator which generates recording data to be recorded onto arecording medium, a synchronizing clock generator which generates asynchronizing clock, and an address signal detector which detects anaddress signal recorded on the recording medium; a recording waveformgenerator having a recording clock generator for generating a recordingclock based on the synchronizing clock and a control interface receptor,for changing a laser emission based on the synchronizing clock and therecording data; a control interface transmitter for controlling therecording waveform generator; and a system control for performing acontrol operation within the apparatus based on an instruction from anexternal device, and wherein the recording clock generator has a clockgeneration/stop function and a response speed changing function, andwherein the system controller transmits a clock generation/stopinstruction and a response speed change instruction to the controlinterface receptor by the control interface transmitter, to control therecording clock generator.
 6. The information recording and reproducingapparatus according to claim 5, wherein a control interface between thecontrol interface transmitter and the control interface receptorcomprises a serial interface that sequentially transmits and receivesinstruction information on a single signal line in 1-bit units.
 7. Theinformation recording and reproducing apparatus according to claim 5,wherein upon reception of a reproduction instruction from an externaldevice, the system controller controls the recording waveform generatorto enter a recording clock stop state via the interface receptor, beforea sector designated by the reproduction instruction comes, while uponreception of a recording instruction from the external device, thesystem controller controls the recording waveform controller to enter arecording clock generator state via the control interface receptor and ahigh speed response state, before a sector designated by the recordinginstruction comes, and after recording was started and recording for apredetermined sector has been made, controls the recording waveformgenerator to a low speed response state.
 8. An information recording andreproducing apparatus comprising: a signal processor having a recordingdata generator for generating recording data to be recorded onto arecording medium, a synchronizing clock generator for generating asynchronizing clock, a recording controller and an address signaldetector; a recording waveform generator, having a clock generator forgenerating a recording clock based on the synchronizing clock andcontrol interface receptor, for changing the amount of laser emissionbased on the synchronizing clock and the recording data; a controlinterface transmitter for controlling the recording waveform generator;an automatic execution circuit for the control interface transmitter;and a system controller for performing a control operation within theapparatus by an instruction from an external device, wherein therecording clock generator has a clock generation/stop function and aresponse speed changing function, and wherein the system controllercontrols the automatic execution circuit via the recording controller,further wherein the automatic execution circuit transmitspreviously-determined clock generation/stop instruction and responsespeed changing instruction to the control interface receptor by thecontrol interface transmitter, to control the recording clock generator.9. The information recording and reproducing apparatus according toclaim 8, wherein in the system controller, a plurality of state settingsto be transmitted to the recording waveform generator are stored in theautomatic execution circuit in advance.
 10. The information recordingand reproducing apparatus according to claim 8, wherein if areproduction instruction is sent from the external device, the systemcontroller outputs the reproduction instruction to the recordingcontroller, and the recording controller outputs a reproduction statesetting transmission instruction to the automatic execution means, afterend of a recording end sector if recording operation is performed uponreception of the reproduction instruction, or after a sector uponreception of the reproduction instruction if recording operation is notperformed then, to control the automatic execution means.
 11. Theinformation recording and reproducing apparatus according to claim 8,wherein if a recording instruction is sent from the external device, thesystem controller outputs a recording instruction to the recordingcontroller, and the recording controller outputs a recording state startsetting transmission instruction to the automatic execution means, afteran end of a reproduction end sector if recording operation is performedupon reception of the reproduction instruction, after end of a recordingend sector if recording operation is performed upon reception of thereproduction instruction, or immediately if reproduction operation andrecording operation are not performed, and wherein the automaticexecution means performs response speed changing setting on therecording controller after recording was started and recording for apredetermined sector has been made.
 12. The information recording andreproducing apparatus according to claim 11, wherein the recordingcontroller does not output the recording state start settingtransmission instruction and a response speed changing settingtransmission instruction to the automatic execution circuit if recordingoperation is performed upon reception of the recording instruction. 13.An information recording and reproducing apparatus for recordinginformation onto a recording medium while changing the amount of laseremission provided in a movable optical pickup unit, comprising: amodulator that generates recording data to be recorded onto therecording medium using a synchronizing clock; a recording waveformgenerator, having a recording clock generator that generates a recordingclock based on the synchronizing clock, that changes the amount of laseremission based on the recording clock and the recording data; and acontroller that controls the modulator and the recording waveformgenerator, wherein the recording waveform generator is formed on acircuit board of the optical pickup unit, and wherein the modulator andthe controller are formed on a circuit board other than that of theoptical pickup unit, further wherein the recording clock generatorgenerates or stops the recording clock based on control by the recordingcontroller, to change a circuit characteristic.
 14. The informationrecording and reproducing apparatus according to claim 13, wherein therecording clock generator generates the recording clock based on thesynchronizing clock sent via a flexible cable.
 15. The informationrecording and reproducing apparatus according to claim 13, wherein afrequency of the recording clock is higher than that of thesynchronizing clock.